Circuit breaker



July 10, 1934. x Q Q w|LM$ 1,966,085

' CIRCUIT BREAKER I Filed Dec. 16, 1929 FIG. 1. 27 E8 FIG'E.

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Patented July 10, 1934 PATENT OFFICE CIRCUIT BREAKER Gustav 0. Wilms, Milwaukee, Wis., assignor, by mesne assignments, to Allen-Bradley Company, Milwaukee, Wis., a corporation of Wisconsin Application December 16, 1929, Serial No. 414,376

12 Claims.

The invention relates to a circuit breaker of the type in which the switch is kept closed under normal electrical conditions by a pawl and .ratchet wheel latch having the ratchet wheel retained in a fixed position by a fusible binder.

The invention has as an object to provide a circuit breaker in which a single push-button or other actuator will suffice to close or open the switch at will.

Another object is to provide a circuit breaker which is simple in construction and efficient in operation. 1

Another object is to provide a circuit breaker which may be readily and economically manufactured. According to the invention as ordinarily embodied in practice, the circuit breaker is provided with a switch having its movable contact binder to retain the ratchet wheel in a'fixed position under normal electrical conditions, an

electric heater arranged to fuse said binder upon the occurrence of abnormal electrical conditions and thereby release the ratchet wheel to allow the movable contact to open the switch, and a single push-button or other actuator arranged to actuate the movable contact to close the switch or release the latch to open the switch.

A circuit breaker embodying the invention is shown in the accompanying drawing in which the views are as follows:

Fig. 1 is a front view with the cover plate omitted.

Fig. 2 is a central vertical section on the line 2-2 of Fig. 1 showing the cover plate in position.

Fig. 3 is a rear view.

Fig. 4 is a sectional plan on the line 44 of Fig. 1.

The circuit breaker has a casing 1 which is preferably made of insulating material and provided with a web or partition 2 to form a front compartment 3 and a rear compartment 4.

The partition 2 has three binding posts 5, 6 and 7 secured thereto and is provided with an opening adjacent each binding post to permit the passage of electric conductors.

A pair of stationary switch contacts are attached to the back of the partition 2 by the binding posts 5 and 6 and extend through the partition 2 into the compartment 3.

The contacts 8 and 9 are normally engaged by a bridging contact 10 carried by a reciprocable plunger 11 which is preferably made of insulating material and extends through an opening 12 in the rim of the casing 1.

The contact 10 has a limited sliding movement relatively to the plunger 11 and is urged down- Band 9 wardly by a spring 13 which is compressed when the contact 10 engages the contacts 8 and 9.

The plunger 11 is urged upwardly, to move the contact 10 out of engagement with the contacts 8 and 9, by a spring 14 which is arrangedin the plunger and bears against a shoulderedpin 15 fixed in the partition 2. v

The pin 15extends through a slot 16 in the plunger 11 to hold the plunger in sliding engagement with the partition 2.

The upper end of the slot 16 is slightly wider than the pin 15 to permit the plunger 11 to move laterally thereon when depressed.

The lateral movement of the plunger 11 is lim-' ited by the sides of the opening 12 and by a rib 17 which is'carried by the partition 2 and sloped slightly relatively to the center 'line of the casing 1.

The contact 10 is normally held in engagement with the contacts 8 and 9 by a catch or pawl 18 which is fixed to the plunger 11 and engages a stationary latch or ratchet-wheel 19.

The ratchet-wheel 19 is fixed by a fusible binder 20, such as solder, to a heat conductor or spindle 21 which extends through the partition 2 into the rear compartment 4.

The heat conductor 21 is secured in the partition 2 and insulated therefrom by a heat insulating bushing 22. 7

An electric heater 23, such as a coil of resistance wire, is arranged in the compartment 4 and surrounds, but is spaced from, the heat conductor 21. v

The terminals of the heater 23 are connected to one of the stationary contacts and to the binding post 7 and the circuit breaker is connected in circuit by connecting the other stationary contact and the binding post 'Iinto the line.

As shown, the circuit breaker is connected in circuit by attaching electric conductors 24 and 25 to the binding posts 5 and 7 and the heater 23 is connected to the binding posts 6 and '7.

When the circuit breaker is closed, the circuit is from the conductor 24 through the binding post 5, the contact 8, the contact 10, the contact 9, the binding post 6, the heater 23 and the binding post 7 to the conductor 25.

The outer end of the plunger 11 is provided with a head 26 having surfaces 27 and 28 arranged at an angle to each other and to the center line of the plunger.

The circuit breaker may be closed and latched in position by pressing upon the top of the head 26 or upon the surface 2'7 .to move the plunger 11 downwardly, bring the contact 10 into engagement with the contacts 8 and 9 and permit the pawl 18 to engage a tooth of the ratchet-wheel 19.

The spring 13 compensates for variations in the position of the teeth on the ratchet wheel 19 and yieldingly holds the contact 10 in engagement with the contacts 3 and 9.

When the pressure on the head 26 is released, the spring 14 tends to move the plunger 11 upwardly and causes the same to pivot upon the pin 15 and abut the rib 17, thus creating a wiping action between the contacts after the same are in engagement.

The circuit breaker may be manually opened by pressing upon the surface 28 which causes the plunger 11 to pivot upon the pin 15 sufliciently to move the pawl 18 out of engagement with the ratchet-wheel 19 and permit the spring 14 to move the plunger 11 upwardly when the pressure upon the surface 28 is released.

The circuit breaker is opened automatically upon the passage of a predetermined current by the heat generated by the heater 23, which is transferred by radiation to the heat conductor 21 and conducted thereby to the binder 20 to fuse the same and permit the ratchet-wheel to rotate, thus permitting the spring 14 to move the plunger 11 upwardly and open the circuit breaker.

After the circuit breaker is opened no more heat is generated by the heater 23 so that the binder 20 quickly hardens and secures the ratchet-wheel to the heat conductor 21.

The plunger may then be depressed to again close the circuit.

During rotation of the ratchet-wheel 19, the same is prevented from moving axially out of alinement with the pawl 18 by the bushing 22 and a lug 29 carried by a cover plate 30 which closes the front compartment 3 and is held in position by a screw 31 threaded into the .pin 15.

The particular casing shown is not provided with a rear cover plate as the same is adapted to fit into a standard outlet box or into an opening in the casing of a motor, the circuit of which is to be controlled by the circuit breaker.

The invention herein set forth is susceptible of various modifications without departing from the scope thereof as hereafter claimed.

The invention is hereby claimed as follows:

1. A circuit breaker comprising a casing, stationary switch contacts carried by said casing, a spring biased plunger arranged in said casing, a movable switch contact carried by said plunger to engage said stationary contacts, a stationary latch fixed in position by a fusible binder, a catch carried by said plunger to engage said latch and hold said movable contact in engagement with said stationary contacts, an electric heater connected in circuit with said fixed contacts to generate heat to fuse said binder and release said latch, and guides for said plunger so arranged in said casing that pressure applied to the outer end of said plunger will cause said movable contact to engage said fixed contacts and said catch to engage said latch and pressure applied to said outer end at an angle to the axis of the plunger will cause said catch to be disengaged from said latch.

2. A circuit breaker comprising a casing, stationary switch contacts carried by said casing, a spring biased plunger arranged in said casing, a movable switch contact carried by said plunger to engage said stationary contacts, a heat conductor carried by said casing, a latch fixed on said conductor by a fusible binder, a catch carried by said plunger to engage said latch and hold said movable contact in engagement with said fixed contacts, an electric heater connected in circuit with said fixed contacts and arranged adjacent said heat conductor to generate heat to fuse said binder, and guides for said plunger so arranged in said casing that pressure applied to the outer end of said plunger will cause said movable contact to engage said fixed contacts and said catch to engage said latch and pressure applied to said outer end at an angle to the axis of said plunger will cause said catch to be disengaged from said latch.

3. A circuit breaker comprising a casing, stationary switch contacts carried by said casing, a spring biased plunger arranged in said casing, a movable switch contact carried by said plunger to abut said stationary contacts and make a sliding engagement therewith as said circuit breaker is closed, a stationary latch fixed in position by a fusible binder, a catch carried by said plunger to engage said latch and hold said movable contact in engagement with said stationary contacts, an electric heater connected in circuit with said fixed contacts to generate heat to fuse said binder and release said latch, and guides for said plunger so arranged in said casing that pressure applied to the outer end of said plunger will cause said movable contact to engage said fixed contacts and said catch to engage said latch and pressure applied to said outer end at an angle to the axis of said plunger will cause said catch to be disengaged from said latch.

4. A circuit breaker comprising a casing having a partition therein, stationary switch contacts carried by said casing, a spring biased plunger arranged in said casing and slidable upon one face of said partition, a movable switch contact carried by said plunger to engage said stationary contacts, a heat conductor supported in said partition and heat insulated therefrom, a latch fixed on said conductor by a fusible binder, a catch carried by said plunger to engage said latch and hold said movable contact in engagement with said stationary contacts, an electric heater arranged upon the other side of said partition adjacent said heat conductor and connected in circuit with said stationary contacts to generate heat to fuse said binder and release said latch, and guides for said plunger so arranged in said casing that pressure applied to the outer end of said plunger at one angle thereto will cause said movable contact to engage said fixed contacts and said catch to engage said latch and pressure applied to said outer end at another angle thereto will cause said catch to be disengaged from said latch.

5. A circuit breaker comprising a casing, a partition arranged in said casing to provide a front and a rear compartment, stationary switch contacts carried by said partition, a spring biased plunger arranged in said front compartment and attached to said partition to slide thereon, a movable switch contact carried by said plunger to engage said stationary contacts, a heat conductor extending through said partition, a heat insulating bushing surrounding said conductor and securing the same in said partition, a latch arranged in said front compartment and fixed on said conductor by a fusible binder, a catch carried by said plunger to engage said latch and hold said movable contact in engagement with said stationary contacts, an electric heater arranged in said rear compartment adjacent said heat conductor and connected in circuit with said stationary contacts to generate heat to fuse said binder and release said latch, and guides for said plunger so arranged in said casing that pressure applied to the outer end of said plunger at one angle thereto will cause said movable contact to engage said fixed contacts and said catch to engage said latch and pressure applied to said outer end at another angle thereto will cause said catch to be disengaged from said latch.

6. A circuit breaker comprising a casing, a partition arranged in said casing to provide a front and a rear compartment, stationary switch contacts carried by said partition, a spring biased plunger arranged in said front compartment and attached to said partition to slide thereon, a movable switch contact carried by said plunger to abut said stationary contacts and make a sliding engagement therewith as said circuit breaker is closed, a heat conductor extending through said partition, a heat insulating bushing surrounding said conductor and securing the same in said partition, a latch arranged in said front compartment and fixed on said conductor by a fusible binder, a catch carried by said plunger to engage said latch and hold said movable contact in engagement with said stationary contacts, an electric heater arranged in said rear compartment adjacent said heat conductor and connected in circuit with said stationary contacts to generate heat to fuse said binder and release said latch, and guides for said plunger so arranged in said casing that pressure applied to the outer end of said plunger at one angle thereto will cause said movable contact to engage said fixed contacts and said catch to engage said latch and pressure applied to said outer end at another angle thereto will cause said catch to be disengaged from said latch.

7. A circuit breaker comprising a casing, a partition arranged in said casing to provide a front and a rear compartment, stationary switch contacts carried by said partition and extending into said front compartment, a plunger arranged in said front compartment and provided with a longitudinal slot, a pin arranged in said slot and fixed in said partition to hold said plunger thereagainst, a movable contact carried by said plunger and having a limited movement relatively thereto, a springurging said movable contact toward said stationary contacts, an operating spring arranged in said plunger and abutting said pin to urge said plunger away from said stationary contacts, a heat conductor supported in said partition and heat insulated therefrom, a latch arranged in said front compartment and fixed on said conductor by a fusible binder,'a catch carried by said plunger to engage said latch and hold said movable contact in engagement with said stationary contacts, and an electric heater arranged in said rear compartment adjacent said heat conductor and connected in circuit with said contacts to generate heat to fuse said binder and release said latch. v

8. A circuit breaker comprising a casing, a partition arranged in said casing to provide a front and a rear compartment, stationary switch contacts carried by said partition and extending into said front compartment, a plunger arranged in said front compartment and provided with a longitudinal slot, a pin arranged in said slot and fixed in said partition to hold said plunger thereagainst, a movable contact carried by said plunger and having a limited movement relatively thereto, a spring urging said movable contact toward said stationary contacts, an operating spring arranged in said plunger and abutting a ratchet-wheel arranged in said front compartment and fixed on said conductor by a fusible binder, a pawl carried by said plunger to engage said ratchet-wheel and hold said movable contact in engagement with said stationary contacts, an electric heater arranged in said rear compartment adjacent said heat conductor and connected in circuit with said contacts to generate heat to fuse said binder and release said latch, a cover plate closing said front compartment, and a lug on said cover plate to hold said ratchet-wheel against outward axial movement during rotation thereof.

9. A circuit breaker, comprising an electric switch, an operating plunger carrying the movable contact of said switch, a ratchet wheel restrained from rotation by a fusible binder, and a pawl carried by said plunger independently of said movable contact to engage said ratchet wheel and disengageable from said ratchet wheel by moving said plunger in a lateral direction away therefrom.

10. A circuit breaker, comprising a casing, an electric switch arranged in said casing and having a. movable contact, an axially and laterally movable operating plunger connected to said movable contact in said casing and arranged to urge said contact to an initial position, a ratchet wheel carried by said casing and restrained from rotation by a fusible binder, a pawl carried by said plunger independently of said movable contact and in position to engage said ratchet wheel 'to hold said movable contact away from its inhold said movable contact away from its initial position and disengageable from said ratchet wheel upon'tilting movement of said plunger to release said movable contact and allow it to return to its initial position.

'12. A circuit breaker, comprising a casing, a stationary contact member mounted in said casing, a movable contact member arranged to engage said stationary contact member, a plunger arranged to slide axially in said casing to engage said movable contact member with said stationary contact member and arranged to be tilted within said casing, means tending to move said movable contact member out of engagement with said stationary contact member, a ratchet retained in stationary position within said casing by a fusible binder, a pawl arranged upon said plunger independently of said movable contact and to engage said ratchet to hold said movable contact member in engagement with said stationary contact member and arranged to be tilted out of engagement with said ratchet upon tilting said plunger to release said plunger and allow said movable contact member to move out of engagement with said stationary contact member, and means to heat said fusible binder to release said ratchet and allow said pawl and said plunger to move to permit said movable contact member to move out of engagement with said stationary contact member.

' GUSTAV O. WILMS. 

